1. Technical Field
This invention relates to rasps and, more particularly, to a drywall rasp for smoothing the edges of a drywall panel at either a 45 or 90 degree angle.
2. Prior Art
Drywall, also known as wallboard, is made in part from gypsum and is supplied in the form of sheets which are then mounted to walls, ceilings and other structures to present an aesthetic, smooth surface. When sheets of drywall are being installed, it is often necessary to cut these sheets to size on the job. One common method of cutting drywall involves scoring the sheet with a sharp blade or other hand tool after which the sheet may actually be broken along the scored line by bending. The broken edge is invariably rough and must be smoothed prior to installation.
In order to smooth this rough edge, it is not uncommon for the artisan or drywall specialist to turn to the STANLEY® “Surform” rasp. However, this rasp is not specifically designed for the specific task at issue and is often employed for lack of a better device. The STANLEY® rasp is much larger than necessary for the job, is bulky and often slips off the rough cut edge of the drywall when in use. Furthermore, the replacement blades for this tool are expensive and require the use of a screwdriver for installation and removal.
Another implement that is widely utilized commercially for removing material from a cut edge of wallboard is an article known as a wallboard rasp. A conventional wallboard rasp is formed of two major components, namely a handle and an abrading element. The handle is often fabricated from wood as a generally rectangular block, typically about six or seven inches in length, about two inches in width and one inch in thickness. A shallow trough is formed lengthwise down the center of the underside of the block while a pair of longitudinally extending narrow slots or crevices are formed along the sides of the block. The crevices are designed to receive the longitudinal edges of the abrading element.
Conventional wallboard rasps perform their intended function quite adequately. However, they are also the source of many painful injuries. Since the expanded metal abrasive element is wrapped over the outer edges of a supporting block, there is a considerable exposure of sharp surface area that creates painful injuries with only light contact to the skin of a user. As a consequence, users must proceed slowly and carefully when utilizing this implement, which increases the amount of time needed to complete the installation of the drywall. Even so, many injuries result.
Furthermore, the transversely cut ends of the expanded metal present an additional source of injury. While the sheet of expanded metal forming the abrasive element is normally cut to a length slightly shorter than the supporting wooden block that serves as a handle so that the ends of the wooden block extend longitudinally beyond the ends of the expanded metal abrading element, the ends of the abrading element are still quite dangerous. This results from cutting the sheet of expanded metal to size.
When the strips of metal that form the lattice to create a multiplicity of grid openings in the expanded metal are cut, short barbs are left that project outwardly at the cut ends of the expanded metal sheet. These barbs can sometimes become bent forwardly and project beyond the end of the underside of the wooden block handle. This exposure creates a considerable safety hazard. The ends can be capped with a folded over marginal strip of metal which is spot welded to encase therein the cut barbs at the ends of the sheet of expanded metal. However, this adds to the cost of fabrication of the product.
A further shortcoming of the implements described herein above is the fact that they can only b used to smooth a rough surface to a flat 90 degree angle. Thus, when to pieces of drywall are conjoined at a corner one piece is cut a slightly shorter than the other such that the longer piece will overlap the shorter one upon installation. This, unfortunately, results in an unsightly section of gypsum being exposed. It would be advantageous to shape two corner sheets in a manner that allows them to be installed without one piece overlapping the other.
Accordingly, a need remains for a drywall rasp in order to overcome the above-noted shortcomings. The present invention satisfies such a need by providing a rasp that is easy and convenient to use, lightweight and compact in design, safe to use and reasonably priced. Such a drywall rasp advantageously allows a user to smooth rough edges to either a 45 or a 90 degree angle depending on where the sheets of drywall are installed. Drywall contractors, along with do-it-yourself enthusiasts, find this new design for a drywall rasp quite helpful, in that it can be used in all situations.